Looking for ideas for midbass drivers for compact size HT speakers... - AVS Forum
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post #1 of 6 Old 07-17-2013, 12:55 AM - Thread Starter
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Design goal here is to build compact home theater speakers (no more than ~0.5ft^3 internal volume). I want to maximize dynamic reach and minimize distortion in the intended passband. I want a midbass driver than can deliver a good clean and efficient performance in the ~80-1800hz range. I'll likely be crossing to one of the more robust Vifa domes like the DX25 with an aggressive passive network. I'd like all 5 speakers to be compact upright 2-way TM configurations. Think MTM output from a compact TM here.

Dynamic goals are to be able to achieve ~110db@1M or better from any single speaker in the system with reasonable linearity. (doesn't need to be perfect at this level, I just want to know that they could hit this level on the occasional transient without biting my head off with distortion)

I don't want to spend more than ~$80 per driver. Less would be better.

Current contenders are:

Eminence Beta 6A
MCM 55-3550 (please note the xmax rating of this driver in the spec sheet can be misleading, the useful xmax is much more than listed in this case)

The 6A would have better upper frequency performance (lower distortion, wider dispersion) and less thermal issues when driven hard for long periods of time, while the 55-3550 would have lower distortion in the sub ~240z range than the 6A due to it's low Fs high motor strength design. (The 6A would be reaching out below Fs on it's high Q response shelf to make ends meet, while the MCM driver would still be over an octave above Fs at x-over to the sub/s).
With enough power (>150W), either of these drivers can achieve ~110db@1M peaks in their intended pass-band here with an 80hz high pass in place in ~0.33ft^3 boxes and 4dB step loss accounted and corrected for while maintaining reasonable linearity.

What I'm looking for is other suggestions just so I know I have covered all possible avenues in the research phase of this project. A well executed underhung driver design would go a long way here to helping me reach my goals if anyone has such a beast with the right characteristics. (the TB 6.5" doesn't have the right characteristics for this job unfortunately)

I'll probably drive these with either a Denon 2313 or 3313 receiver. I don't want to get into separates for amplification of the mains so I'm not interested in any driver options that would require esoteric amplification to achieve these dynamic goals.

To put it simply, any driver up to ~8" in size with a real 2pi efficiency of ~92dB@1W1M or better that is capable of displacing ~60cm^3 or better can probably fit into the contenders list here. I know there are a whole bunch of 8" pro-sound "monitor" oriented drivers out there that are over the $100/ea price point that can meet the design goals of this project all day with enough amplification. I just hate to spend that much per driver.. Maybe if I can convince myself to drop the sophistication and capabilities of the rear channels then I could afford to ramp up the front channels with some of those B&C and RCF 8" midbass options.


Just found the Celestion TF0818. I think I may have to move this to the top of the list!

Thank You,
Eric
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post #2 of 6 Old 07-17-2013, 01:10 AM
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Have you checked out Parts Express's Dayton Audio drivers? I have been impressed with their quality. How about Peerless? For that matter, what about Vifa? I made some ported Vifa speakers using a 5.25" driver that kicked some serious butt for its size.
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post #3 of 6 Old 07-17-2013, 04:35 AM
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As the above poster mentioned, I believe that Dayton has some really good mid-bass-mid-woofers such as the RS180, or some other Dayton RS series driver. I just do not know if that particular tweeter can hit that 110db SPL number without generating distortion. If it were me, I would go with a Seos based design such as the Fusion, Tempest, or any other Seos design. Go to diysoundgroup.com and look some of these speakers over. They would most certainly reach your desired SPL numbers while also having great imaging and clear/detailed sound.
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post #4 of 6 Old 07-17-2013, 10:49 AM - Thread Starter
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I'm not aware of any Dayton, Peerless, or Vifa branded midbass drivers in this size class that have the EBP necessary to reach these levels without esoteric amplification and potential thermal issues. They aren't on the list of contenders because I already know they won't make the cut. I'm looking for drivers up to 8" diameter with an EBP over 150. The Celestion TF0818 is by far the best contender I have found so far with headroom to spare.

The SEOS/duysoundgroup stuff has come a long way with a lot more products than the last time I head about this stuff. Just wish there were a wave-guide that wasn't so big. I really want these speakers to be compact. ~9x13" baffle size is about the upper end limit here.
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post #5 of 6 Old 07-17-2013, 11:00 AM
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Funny, I to have been considering a design with either the Clestion 8" or the Eminence Beta 6 smile.gif I think the Morel CAT378 would be a good tweeter match, that or maybe the SB29.

I think you've done a good job looking through what is available.
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post #6 of 6 Old 07-19-2013, 04:44 AM
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Got to look at the Eminence Alpha 8 and Beta 8. Might need to go a little over 0.5 ft^3 to get your 80 Hz number where you want it but they will hit your 92 dB/w/m target. I forget which one the 1pi teams up with the DX25. http://www.pispeakers.com/catalog/default.php/cPath/3
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